Pen cap



FIG. 1 is a bottom, right rear perspective view of a pen cap showing my new design;

FIG. 2 is a left side elevational view, the right side being a mirror-image thereof;

FIG. 3 is a front elevational view;

FIG. 4 is a rear elevational view;

FIG. 5 is a bottom plan view;

FIG. 6 is a top plan view; and,

FIG. 7 is a left side elevational view with the outer wall shown partially broken away for convenience of illustration. 

The ornamental design for a pen cap, as shown and described. 